import java.util.Scanner;

public class Test {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String arrays= scanner.nextLine();
        //字符串长度最大为100且字符串不能为空
        if(arrays==null&&arrays.length()>100){
            return ;
        }
        //将arrays的第一个值添加到arrays2中
        String arrays2=String.valueOf(arrays.charAt(0));
        for (int i = 0; i < arrays.length(); i++) {
           if(!arrays2.contains(String.valueOf(arrays.charAt(i)))){
               arrays2=arrays2+arrays.charAt(i);
           }
        }
        System.out.println(arrays2);
    }
}
